The protection of a motor vehicle against illegal confiscation, viz theft, has been accomplished before through the installation of a hidden fuel shutoff valve. When such a valve is turned "off", the protected vehicle is allowed to start up in a normal way and operate for a brief period of time during which it consumes the limited amount of fuel contained in the carburetor bowl, etc. This limited operation of the engine encourages the thief to drive the vehicle from its obscure location where the thief feels safe, to a more public view where continued theft activity would be discouraged by exposure. Furthermore, the time the vehicle operates before the limited fuel is consumed will vary from one vehicle to another due to differences to residual fuel left after the cutoff valve, and the vehicle's consumption rate. The time will also vary in any given vehicle depending on the presumably illicit driver's driving style, e.g. racing the engine will consume the limited amount of fuel more quickly than a liesurly, idle speed driveaway. The inclusion of such cutoff devices have limited popularity because it involves difficult, costly installation which has limited variability in the choice of a good hidden location for the shutoff device.
It therefore appears to me that a means for producing the same kind of desired irregular time duration limited drivability effect prior to total vehicle disablement is desirable. If such a device can be easily installed at low cost and without intercoupling with the vehicle's fuel system. The limited operation of the vehicle electrical ignition system is selected by me as the best embodiment for my invention, in that intercoupling with the ignition system is easily undertaken, even by the "Saturday afternoon mechanic". Since the operation is entirely electric in nature, the secret switch can be situated in a multitude of locations unique to each operator's choice. This advantage of course makes the switch discovery much more unlikely, even by a skilled potential thief. The likelihood of easy discovery is largely determined by the ingenuity of the individual installer's choice of location options. Additionally, the hidden switch may be key operated.
The resulting theft deterring effect which would be desirable would produce an experience quite similar to that now produced by fuel cutoff, wherein the vehicle starts up, but then soon exhibits erratic running behaviour which shortly becomes progressively worse, or else the vehicle falters altogether in its operation after a short period of semmingly normal operation. This false start generally serves to enable the thief to have to expose himself in a way that should lead to his abandonment of the theft project. It also produces the illusion of faulty vehicle operation, which may discourage the thief.